Hand-held instant bar code reader having automatic focus control for operation over a range of distances

ABSTRACT

A hand-held bar code reader includes one or more photosensor arrays which provide a plurality of image sensor portions arranged for receiving images of a bar code through a plurality of selectively usable paths of 5 different focal lengths which are defined by a passive optical system. A distance measuring system controls the sensor portion which is used to control the focal length. In one embodiment, the bar code image is projected to a plurality of receiving mirror surfaces, thence to a plurality of additional mirror surfaces and thence through lens barrels to mirrors which project the 10 images to photosensor arrays. In another, the bar code image is projected to a plurality of receiving mirror surfaces, thence to an additional mirror surface, and thence through a single lens barrel to a mirror which projects the images to a photosensor array.

CROSS REFERENCES

A. Related Applications

The present application is a continuation-in-part of application Ser.No. 07/947,036 filed Sep. 16, 1992, now U.S. Pat. No. 5,308,966 issuedMay 3, 1994, which is a continuation of U.S. Ser. No. 07/875,791, Apr.27, 1992, now abandoned, which is a continuation-in-part of U.S. Ser.No. 07/422,052, filed Oct. 16, 1989, now abandoned, which is a divisionof U.S. Ser. No. 06/894,689, filed Jun. 5, 1992, now U.S. Pat. No.5,235,317, issued Oct. 31, 1989. The disclosure of U.S. Ser. No.07/422,052, is incorporated herein by reference.

B. Incorporations by Reference

The following related commonly owned patent applications areincorporated herein by reference:

    ______________________________________                                                                              Issue                                   Inventor(s)                                                                            Serial No.                                                                              Filing Date                                                                             Patent No.                                                                             Date                                    ______________________________________                                        White    06/905,779                                                                              09/10/86  4,882,476                                                                              11/21/89                                Miller,  07/136,097                                                                              12/21/87                                                   et al                                                                         Danielson,                                                                             07/143,921                                                                              01/14/88                                                   et al                                                                         Koenck   07/238,701                                                                              08/31/88                                                   Main, et al                                                                            07/321,932                                                                              03/09/89                                                   Danielson,                                                                             07/364,902                                                                              06/08/89  WO/90/16033                                                                            12/27/90                                et al                                                                         Chadima, 07/339,953                                                                              04/18/89  4,894,523                                                                              01/16/90                                et al                                                                         Danielson,                                                                             07/422,052                                                                              10/16/89  4,877,949                                                                              10/31/89                                et al                                                                         Phillip Miller                                                                         07/347,602                                                                              05/03/89                                                   et al                                                                         Koenck   07/987,574                                                                              12/08/92                                                   ______________________________________                                    

The subject matter of certain of the above cases has been published asfollows:______________________________________U.S. Ser. No. RelatedPublication PublicationDate______________________________________06/905,779 U.S. 4,882,47611/21/8907/364,902 WO 90/16033 12/27/9007/422,052 U.S. 4,877,94910/31/8907/339,953 U.S. 4,894,52301/16/90______________________________________

The entire disclosures of the foregoing publications are incorporatedherein by reference.

AUTHORIZATION PURSUANT TO 37 CFR 1.71(D) AND (E)

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

BACKGROUND OF THE INVENTION

The present invention is particularly concerned with improvements ininstant bar code readers of the type shown in U.S. Pat. Nos. 4,282,425and 4,570,057. The disclosures of these U.S. patents are incorporatedherein by reference by way of background.

The instant type of bar code reader with flashable illuminator means hasproved to be extremely desirable for portable applications because ofits unique simplicity and compact design. A significant goal of thepresent invention is to retain the major advantages of the presentcommercial instant bar code readers with flashable illuminator meanswhile enhancing the capacity for reading bar codes of substantiallygreater length. An important related aspect of the invention is toenable the reading of such large labels by illuminating the same with aninstantaneous flash of light while the labels are at a greater distancefrom the frontal end of the reader. A further development goal is tomore effectively adapt the reading operation both to close up bar codelabels of high reflectivity and to labels at greater distances and ofcurved configuration.

SUMMARY OF THE INVENTION

The present invention is therefore particularly directed to theprovision of an instant bar code reader which, while retaining theadvantages of simplicity, ease of hand operation and ruggedness,achieves enhanced versatility by its ability to read bar codes ofgreater length and to adapt to a greater range of reading distances.Such enhanced versatility is realized by providing the reader with anautomatically controlled lens system and operating such control inaccordance with a measure of reading distance. Further improvements areachieved by monitoring an average of reflected light from the bar codeduring a reading operation, and terminating integration of the reflectedlight from a bar code after an optimum measurement sample of thereflected light image has been received.

Aiming of the reader may be carried out with the assistance of visiblemarker light beams directed into the field of view of the reflectedlight image sensor. In an ideal embodiment, the marker beams extend fromopposite ends of the bar code image sensor through the reflected lightoptics so that the beams delineate the desired locations for theopposite ends of a bar code in the reader field of view.

For the sake of energy conservation during portable operation, automaticcontrol of the lens system may be disabled until such time as the barcode is within an effective reading range. Where a capacitor dischargeenergizes a flashable illuminator, the capacitor discharge current maybe interrupted as soon as an adequate amount of reflected light has beenreceived; this not only reduces battery drain but also speeds up thecapacitor recharging cycle. By monitoring the charge on the capacitor, anew reading cycle can be initiated after a minimum time lapse, should aninitial reading cycle be unsuccessful. Accordingly, it is an object ofthe invention to provide a bar code reader configuration particularlysuited to hand held operation while exhibiting increased versatility.

A more specific object is to provide a bar code reader capable ofreading a wider range of bar code sizes without sacrifice of essentialsimplicity and ease in hand held operation.

Another object is to provide a bar code reader capable of rapid andefficient alignment with bar codes located at substantial distances fromthe reader.

A further object of the invention is to provide an instant bar codereader which achieves the foregoing objects while minimizing energyconsumption so as to retain a capacity for extended portable operation.

A feature of the invention resides in the provision of an adaptive barcode image sensor system enabling a succession of readings of a givenbar code with reflected light from respective different segments of suchbar code controlling respective integration times. This feature isapplicable for example to bar code labels of a curvature such that a barcode reading with a single integration time would not effectively samplereflected light from all segments of the label.

Further features leading to enhanced adaptability of the code imagesensor system comprise individually operable flash illumination meansenabling more rapid flash sequences, and/or enabling improvedillumination of irregular or curved code configurations and/or of codeconfigurations of greater extent, and/or enabling respectiveindividually controlled flash durations immediately following eachother, and e.g. adapted to respective different segments of a codeconfiguration.

Still further features of an adaptive code image sensor system relate tosimultaneous reading of code segments at markedly different depths offield and/or multiple depth measurement sensors for assessing the depthof respective segments of a code configuration, and/or selectable imagesensors effectively adapted to read code configurations at respectiveoverlapping depth ranges for instantaneous adaptation to a codeconfiguration at any depth over a wide range without the use of movingparts. In one implementation, the depth of field of a lens system isgreatly increased by providing multiple optical image paths ofrespective different lengths in the reader which lead through the lenssystem to respective independently controllable image sensors.

Another feature resides in the provision of a marker beam indicatorsystem for delineating the optimum location for a bar code in the readerfield of view so that the reader can be positioned rapidly andefficiently even while at substantial distances from a bar code. Variousmethod features will be apparent from the following disclosure. Forexample, in a case where a curved bar code label has a central segmentwithin the focal depth of the lens system, but the marginal segments areactually outside the focal depth, one exemplary method of programmedoperation may provide for a second flash automatically after the lenssystem has automatically focused at a selected greater depth. Byassembling the two readings, e.g. pixel by pixel, a good bar codereading may be obtained with e.g. valid start and stop characters beingobtained from the second reading. In another method of programmedoperation, a display forming part of the operator input/output means caninstruct the operator to take first a reading of the left hand portionof a severely curved label, then a central portion and then a right handportion, with the processor assembling the pixels of the respectivereadings to obtain a complete bar code image reading.

The operator could, in another mode, advise the reader processor, e.g.,by the selective actuation of function keys or the like, of a particularreading sequence to be input to the reader processor for extremely longor sharply curved labels. The function keys could be part of a keyboardassociated with the reader itself and/or a keyboard associated with ahost computer unit directly mechanically coupled with the readerhousing, or coupled via any suitable remote linkage means such as acable or a radio frequency channel. In certain instances, the readerprocessor may assemble the pixels of successive readings not only withthe assistance of internal check characters and preknowledge of codeformats and the like and/or of specific reading sequences, but furtherwith the assistance of measurements from multiple distance measurementsensors defining the general bar code spacial configuration. Utilizingmultiple flashable illuminators and/or multiple intensity sensors mayenable valid reading of different segments while avoiding in all cases,any saturation of CCD charge wells or the like of an image sensor.Saturation of any part of a CCD shift register may adversely affectsubsequent operation of an image sensor.

Other objects, features and advantages of the invention will be apparentfrom the following detailed description taken in conjunction with theaccompanying sheets of drawings, and from the features and relationshipsof the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a preferred embodiment of thepresent invention;

FIG. 2 is a diagrammatic view useful for explaining certain features ofa specific exemplary embodiment of the invention;

FIG. 3 is a somewhat diagrammatic partial longitudinal sectional viewfor indicating the application of certain features of the presentinvention to is an instant bar code reader generally as shown in U.S.Pat. No. 4,570,057;

FIG. 4 is a somewhat diagrammatic plan view illustrating an adaptive barcode image sensor system in accordance with the present invention, andalso illustrating an alternative label guide indicator arrangement forthe reader of FIG. 3;

FIGS. 5, 6 and 7 are electric circuit diagrams for illustrating anexemplary implementation of component 11 of FIG. 1;

FIGS. 6A through 6F show waveforms useful for explaining the operationof the circuit of FIG. 6;

FIGS. 8 and 9 show an exemplary implementation of components 15, 16 and17 of FIG. 1;

FIG. 10 is an electric circuit diagram for illustrating an exemplaryimplementation for component 121 in FIG. 1;

FIGS. 11 and 12 are diagrammatic illustrations for indicating anexemplary implementation of component 20 in FIG. 1; and

FIGS. 13 and 14 illustrate examples of alternative arrangements inaccordance with the invention.

DETAILED DESCRIPTION

FIG. 1 illustrates a preferred instant bar code reader system forextending the versatility of a commercial bar code reader such as shownin U.S. Pat. No. 4,570,057. Component 10, FIG. 1, may represent acontrol and processing means for the system and may include a centralprocessing unit, memory units and analog to digital conversion channels.

The central processing unit and associated memory form the main controlportion of the system. The other functional blocks of FIG. 1 maybeinputs or outputs with respect to the central processing unit. Thecentral processing unit may be a microprocessor that executes theprogram to control the operation of the reader. The microprocessor actsas a microcontroller with the capability of sensing and controlling thefunctional elements of the bar code reader, and decoding the bar code assupplied from a bar code image sensor means 11. Where the reader iscoupled on line with 15a host computer system, (for example by a hostconnection means in the form of a flexible cable), the decoded barsignal is transmitted to the host under the control of the centralprocessing unit. The microprocessor is capable of static operation withshut-down for power conservation. Wake-up of the processor will occurwhen an operator actuates a scan switch 12.

An electrically erasable read only memory of component 10 may beutilized to store parameters and special modifiable decoding sequencesfor the bar code reader operation. Examples of these parameters would belabel code, and input/output speed and control format. Component 10 mayalso include a random access memory for data collection, decoding workspace and buffer storage of the decoded label data for transmission to ahost computer, for example. The random access memory can be internal tothe microprocessor chip or reside on a data bus. The analog/digitalchannels are for receiving the bar code signals generated by the barcode image sensor means 11 and for other purposes as will be hereafterexplained.

The image sensor means may, for example, include a photosensor arrayindicated diagrammatically at 13 having a one dimensional linear arrayof photodiodes for detecting the bar code reflection image. To readlabels with bar code lengths of greater than seven inches with highresolution requires that the array have relatively high resolution. Byway of example, the array 13 may comprise five thousand photodiodecircuits (5,000 pixels) and provide approximately three photodiodecircuits (3 pixels) for each five mils (0.005 inch) of a bar codelength. (Each pixel of array 13 may have a length of about sevenmicrons.) A charge coupled device (CCD) shift register may be arrangedto receive bar code signal elements from the respective photodiodecircuits after a suitable integration interval. Once the bar code signalelements have been transferred to the shift register, the signalelements are retained independently of further exposure of thephotodiodes to reflected light from the bar code.

In the embodiment of FIG. 1, an intensity sensor 14 is provided and maycomprise a photodiode that will determine the relative amount of lightexposure of the photosensor array 13 if component 10 operates atsufficiently high speed, the signal from the intensity sensor 14 may besupplied exclusively to component 10 via an analog/digital channel sothat the control and processing means can determine the optimum pointfor transfer of the bar code image signals to the shift register.

In a presently preferred implementation, however, the intensity sensormean 14 is directly coupled with the hardware control circuits of theflashable illuminator means and of the bar code image sensor means, andthis is indicated by dash lines L1 and L2 in FIG. 1; in this case, lineL is used only so that the processor component 10 is advised that aflash has actually occurred. In a preferred embodiment wherein aflashable illuminator 15 is driven by capacitor discharge current, acomponent 16 may effect interruption of the flow of current from thecapacitor based directly on the signal supplied via LI from intensitysensor 14. In this way, energy is conserved, and recharging of thecapacitor speeded up. Component 16 may comprise a flash currentinterrupter switch means, e.g., a solid state switch which is controlledto interrupt discharge of the capacitor of high voltage generation unit17, and thus, to terminate the flash of light from the flashableilluminator 15 when intensity sensor 14 indicates that adequatereflected light has been received from a bar code.

The system of FIG. 1 is also indicated as including a reading distanceadaptation means 20, label guide indicator means 21 and reading distancesensor means 22. These components are best understood by reference to aspecific example as shown in FIG. 2. FIG. 2 illustrates an exemplaryconfiguration wherein the label guide indicator means 21 is provided bya pair of marker light emitting diodes 24 and 25 which produce lightbeams 26 and 27 extending from opposite ends of the photosensor array 13through the lens system indicated at 30 so as to delineate by means ofmarker light spots at 28 and 29 on the label the field of view of thereader. FIG. 2 illustrates a situation where label 31 has a bar codewith a length greater than seven inches and is located at a distance Dfrom a frontal window part 33 of the reader of greater than two inches,for example, three inches. By way of example in FIG. 2, flashableilluminator 15 of FIG. 1 is illustrated as being implemented by twoflash tubes 35 and 36 directed obliquely outwardly relative to a centralaxis 37 of the reader. FIG. 2 also illustrates the provision of anultrasonic transducer 38 for implementing component 22 of FIG. 1. Forexample, transducer 38 may emit an ultrasonic pulse along an axis 39aligned with the reader central plane such that the time of arrival of areflected pulse from the bar code label 31 provides a measure of readingdistance. In place of or in addition to distance sensor 38, infrareddistance measurement sensors 38-1 and 38-2 are provided in FIG. 2, withaxes arranged to intersect a curved label generally at a mean distance(e.g. at D0 equal to one-half the sum of the maximum distance D1 and theminimum distance D11). By way of example, adaptation means 20 mayinclude motor driven focus adjustment means 40 coupled with the lenssystem 30 for adjusting the lens system parallel to the central opticalaxis 37, as represented by the double-headed arrow 41. In the example ofU.S. Pat. No. 4,570,057, the reader has a width dimension at its frontalwall which is greater than the extent of the exit light path at theplane of such frontal wall. However, in the specific configuration ofFIG. 2, it will be observed that marginal light rays 43 and 44 from theflash tubes 35 and 36 are transmitted by transparent side walls 45 and46 of the reader housing so that in this case the illumination field hasa total extent at the plane of the reader frontal wall which issubstantially greater than the width dimension of such frontal wall.

In FIG. 2, a photodiode intensity sensor 50 corresponding to component14 of FIG. 1 is indicated as being mounted centrally as defined by aplane intersecting the optical axis 37, but offset from photosensorarray 13 so as not to obstruct light incident thereon. (Optical axis 37intersects photodiode array 13.) Intensity sensor 50 is preferablyplaced so as to intercept light of maximum intensity as reflected fromthe label 31. By way of example, intensity sensors such as 50, 51 and 52may be located at respective different locations adjacent sensor array13 as indicated, and successive ones of the sensors may be selected foractual control of bar code image integration time during successive barcode reading operations for a given curved bar code configuration aswill be hereafter explained.

In the example of FIG. 2, mirror elements 53 and 54 are mounted atopposite ends of photosensor array 13 for reflecting light from thesources 24 and 25 along the beam paths 26 and 27. Components such as 11,14, 15, 20, 21 and 22 of FIG. 1 may be implemented as shown in FIG. 3.FIG. 3 may be taken as supplementing FIG. 2, and corresponding referencenumerals have been used in FIGS. 2 and 3 to designate similar parts.

Referring to the physical arrangement of parts as indicated in FIG. 203,the location of the intensity sensors such as 51 to one side of acentral optical axis 60 is indicated. Considering the plane whichintersects the photosensor array 13 and coincides with the optical axis60, it will be understood that mirrors such as 53 will each have alocation centered on such plane. As indicated in FIG. 3, ultrasonictransducer 38 may be located just above window 33 with its axis 39directed generally parallel to the optical axis 64 (which indicates theaxis for the reflected light entering the reader).

In conformity with FIG. 2, the reader is shown as having transparentside wall portions such as 46 at the respective sides of the reader,corresponding to the transparent portions 45 and 46 in FIG. 2. Each ofthe flash lamp tubes 35 and 36 may be provided with a housing 75 and aninterior reflector 76 with a configuration as described as U.S. Pat. No.4,570,057. At a depth of approximately three inches in front of thewindow 33, the flash illumination means 35 and 36 may effectivelyilluminate a sensing region having an extent greater than seven inches,for example.

Reflected light from a bar code label 31 follows an optical path asindicated at 64, 80, 81 and 60 in FIG. 3 by virtue of the arrangement ofmirrors 82, 83 and 84. These mirrors are fixed relative to readerhousing 86, while a lens barrel 90 carrying optical lenses is axiallyadjustable relative to the reader housing. Also preferably forming partof the adjustable lens barrel assembly 90 are an infrared rejectingfilter 97 and a rectangular aperture element analogous to that of U.S.Pat. No. 4,570,057. For the sake of diagrammatic indication, barrelassembly 90 is shown as having a series of gear teeth 101 meshing with aworm gear drive 102 which is driven from an adjustment motor 103 via aright angle drive coupling assembly 105. The barrel assembly 90 may havea range of adjustment so as to accommodate bar code labels closelyadjacent to the frontal window 33 and at progressively greater distancesin front of the window 33 up to reading distances of at least threeinches.

In FIG. 3, a bearing for the shaft of worm gear 102 is indicated at 111.Guide means for lens barrel 90 are indicated as comprising flanges suchas 112 for riding in cooperating slot-like low friction guideways suchas 114. An alternative location for the light emitting diodes 24 and 25is indicated at 24-1 in FIG. 3. An analog to digital conversion channelof component 10, FIG. 1 may be utilized to monitor charge build-up inthe high voltage generation component 17 so that a flash of theilluminator means 15 will take place only when the desired amount offlash driving current is available.

Other analog to digital conversion channels may read the light intensityvalues accumulated by intensity sensors 50, 51 and 52, so that suchintensity values can determine respective bar code image integrationtimes, where desired.

Component 120 in FIG. 1 represents-desired audio and visual statusindicators for facilitating operation of the reader unit. For example, ared-light-emitting diode indicator may be energized whenever a thumbactuator controlling read enable switch 12 is pressed and the readingdistance sensor means determines that a bar code label is beyond themaximum reading distance of the reading distance adaptation means 20. Atsuch a distance outside of the operative reading range, the lensadjustment motor 103, FIG. 3, may be disabled, e.g., by the programmingof control and processing means to conserve power. When the reader iswithin the operative range, if the thumb operated switch 12 is actuated,motor 103 is essentially continuously controlled according to successivedistance readings. If a good bar code reading is accomplished, means 120may produce a relatively long single beep and turn on a green lightemitting indicator diode. Where a bad bar code reading situation isdetermined, e.g., after a selected number of reading attempts, means 120may generate three short beeps, for example. The programming may be suchthat once a good reading or bad reading condition is determined, theuser must release the thumb switch and depress it again to initiateanother read sequence. Indicator lamps and a beeper have been shown inthe seventh FIG. of U.S. Pat. No. 4,570,057 and are described therein atcolumn 11, lines 37-43. The indicator lights may be physically locatedforwardly of the thumb switch as can be seen in the first FIG. of U.S.Pat. No. 4,570,057.

FIG. 1 also indicates an input/output buffer component 121 for couplingthe control and processing means 10 with a host processor or the like. Aconnection means 122 may directly receive a host processor so that thehost processor housing is physically attached with the reader housing.As another example, connection means 122 may comprise a cable containingsix conductors. Preferably, such a cable would be detachable at thereader. In this second example, all needed voltages may be generated inthe reader from plus five volts supplied by two of the six conductors(+5 V, GND). The other four signal lines of the cable are preferablyindependently programmable as inputs or outputs. By way of example, thehost processor may be part of a portable hand held computer such asshown in U.S. Pat. Nos. 4,455,523 and 4,553,081. The rechargeablebatteries of the portable computer may supply all needed power to thereader unit of the present invention. In the second example, a hostcomputer unit can be carried in a belt holster for example duringextended use of the reader unit of the present invention.

FIG. 4 is a somewhat diagrammatic top plan view of an exemplary bar codeimage sensor means 11 such as indicated only schematically in FIG. 1. InFIG. 4, the sensor housing 124 is shown as having a light transparentcover window 125 overlying the photodiode array 13. Where the photodiodearray comprises five thousand individual elements or pixels, each with adimension of about seven microns, the intensity sensors 50, 51 and 52may each have a length of about one-tenth inch or more so as to spanmany bars of a reflected bar code image, e.g., at least six bar codeelements, and reliably sense an average intensity value which isessentially independent of any specific bar code sequence. By way ofexample, the intensity sensors may be cemented to the exterior surfaceof window 125 at successive locations along photodiode array 13 butoffset from the light entrance path to the photodiode array.

Mirrors 53 and 54, FIG. 2, may be cemented in place on the glass 125 asindicated for mirrors 53' and 54' in FIG. 4. The light sources 24' and25' in FIG. 4 may be located in wall 130, FIG. 3, at a section asindicated 24-1 in FIG. 3. The mirrors 53' and 54' are secured at anglessuch that the marker beams will extend parallel to the image path at 60,81, 80 and 64 and will produce spots of visible light, e.g., of redcolor, corresponding to spots 28 and 29 in FIG. 2, and spot 28 asindicated in FIG. 3.

In a preferred mode of operation of the embodiments of FIGS. 1-4, manualactuation of the read enable switch 12 will initiate a flash of theilluminator means 15 provided the reader is within its operative rangefrom 20a bar code label. If the reader is outside of such operativerange, momentary actuation of the read enable switch 12 will activate apair of marker beams such as 26, 27, FIG. 2 representing the lateralmargins of the reader field of view. Then, if the reader is moved intooperative range and the read enable switch 12 again actuated, theilluminator means 15 will be flashed regardless of the state of focus ofthe automatically adjustable lens means 30, FIG. 2.

If the initial reading is found to be invalid, the marker beams willautomatically be turned on briefly to again delineate the reader fieldof view, and quickly thereafter the illuminator means will be flashedagain. This sequence can be repeated automatically (if the read enablebutton is held depressed), until the lens means 30 has beenautomatically adjusted for the distance of the bar code from the readerand a valid reading is obtained.

In the reading of a highly curved bar code label, a plurality ofreflected light intensity sensors such as 50, 51 and 52, FIG. 4, may besuccessively activated in successive flashes of the illuminator means15, the intensity sensors automatically controlling successiveintegration times of the bar code image sensor 11, according to theaverage intensity of reflected light from respective different segmentsof the curved bar code. Respective segments of a curved bar code label131 have been indicated at 150, 151 and 152 in FIG. 2. In a first flashillumination of label 131, intensity sensor 51 might measure thereflected light from a bar code segment 151 on the label and causetransfer of the bar code image signals to a receiving means such as aCCD shift register after an integration time optimum for the reading ofbar code segment 151. In a second flash quickly following the first, theintensity sensor might control integration time so as to be optimum forthe bar code segment 152. Then in a third flash illumination of the barcode 131, the central intensity sensor 50 could control integrationtime. The control and processing means 10 would then assemble readingsfor bar code segments 151, 152 and 150 from the successive flashes ofilluminator means 15 to determine if a valid total reading had beenobtained. If not, a further succession of three flashes of theilluminator means could be enabled, with the indicator beams 28, 29being turned on in the interval while proper high voltage was buildingup for the further series of flashes. (Three capacitors of component 17,FIG. 1, could store charge and be discharged rapidly in succession toproduce three flashes in rapid sequence without any delay for capacitorrecharging.)

For the case of a highly curved bar code label such as indicated at 1311in FIG. 2, distance sensors 38-1 and 38-2 might indicate that themargins of the bar code would be out of focus. In such a case, aspreviously mentioned 25 in the introduction to the specification, theprocessor 10 could be programmed to flash both tubes 35 and 36 with theadjustment means 40 controlled according to the distance reading D2 assensed by the distance measurement means 38. Thereafter, control of theadjustment means 40 would be related to a distance such as indicated atD22 in FIG. 2 so that 30 marginal portions of the label 131-1 would thenbe in focus. With the new focus automatically established, tubes 35 and36 could be again activated so as to read the marginal portions of thebar code on label 131-1, whereupon the processor component 10 couldassemble the two readings pixel by pixel to establish a complete barcode.

In another example as previously mentioned, the reader could be providedwith a display, and the processor component 10 could cause the displayto instruct the operator that the label 131-1 was to be read in twosegments, the reader first being positioned so as to be directed towardthe left portion of the label 131-1, e.g., with only a tube 36 flashed,and then in a second operation, the reader being physically adjusted soas to be directed toward the right hand portion of label 131-1, and, forexample, only the tube 35 flashed.

In another mode of operation as previously mentioned, the reader couldbe provided with a keyboard, and the operator noting the highly curvedconfiguration of label 131-1, could advise the processor component 10that a first reading would be taken of the left-hand portion of label131-1, after which a separate reading would be taken from the right-handportion of label 131-1.

Along with the multiple readings of a highly curved label such as 131-1,the processor 10 could also take account of distance measurements fromcomponents 38, 38-1 and 38-2, in assembling e.g., pixel by pixel, acomplete bar code from the successive readings.

Summary of Exemplary Operation for FIGS. 1-4

Since operation is determined by the programming of component 10, manydifferent modes of operation can be implemented. Generally, however, thereading distance sensor means 22 will be activated to read the distancebetween the front window 33 of the reader and one or more regions of abar code label. If the distance measured, such as D, FIG. 2, is greaterthan an operative range of the adaptation means 20, for example, greaterthan three inches, the adaptation means 20 may be disabled. Thus, forthe case of adjustable lens means 30, the motor driven focus adjustmentmeans 40 would be inactive as long as the distance sensor means such as38 determined that the distance D was outside of the operative range ofthe lens means 30. In this case, however, preferably the label guideindicator means 21 would be active as long as the scan switch 12 wasactuated by the operator, to produce the marker spots as indicated at 28and 29 in FIG. 2 and as indicated at 28 in FIG. 3. The marker beams 26and 27 would remain on while switch 12 was actuated and for an intervalof, for example, five seconds after release of switch 12, where thereading distance remained outside of the operative range.

Where the switch 12 is actuated and the reading distance sensor meansdetermines that the reading distance is within the operative range,component 10 checks the high voltage generation means 17 to determine ifproper high voltage is present on the flash capacitor means and if so,turns off the label guide indicator means 21, FIG. 1, and effects acleaning cycle of the bar code image sensor means 11 so as to preparethe photosensor array 13 for a reading operation. The processorcomponent 10 then initiates a capacitor discharge to activate theflashable illumination means 15. In one embodiment, a single capacitormay be arranged to drive both of the flash tubes 35 and 36 of FIG. 2. Inanother embodiment, respective individual capacitors may be arranged todrive the respective tubes 35 and 36. In one mode, both capacitors maybe discharged to drive both of the tubes 35 and 36 simultaneously. Inthis mode, an intensity sensor 50, FIGS. 2 and 4, may control theduration of the integration time interval during which the reflected barcode image signal is accumulated at the sensor means 11. At the end ofthe integration interval, the bar code image signals are transferred forexample to a CCD shift register for readout from the sensor means 11.During the readout operation, the signals received by the shift registerare not affected by further light impinging on the photodiode array 13.Furthermore, at the end of the integration interval, the flash currentinterrupter switch 16 may be actuated so as to interrupt discharge fromthe relevant capacitor or capacitors. In this way, energy is conserved,and recharging of the capacitor means is speeded up.

In a second mode of operation, a capacitor associated with flash tubemay be activated during a first reading interval under the control of anintensity sensor 51 for insuring an optimum reading of a bar codesegment such as indicated at 151 of a label 131, for example, of markedcurvature. In a second reading interval, the capacitor associated withflash tube 36 may be activated to illuminate particularly a bar codesegment 152, with the integration time of the bar code image sensormeans being under the control of an intensity sensor 52 arranged toreceive reflected light particularly from bar code segment 152. In oneexample, intensity sensor 51 would be arranged to generate an averagelight value by averaging reflected light emanating from a portion 191 ofsegment 151. Similarly, intensity sensor 52 would receive light from aportion such as 192 of segment 152 where reflected light intensity wouldbe greatest on the average. In this example, the programming ofcomponent 10 would be such as to generate the bar code from twosuccessive flashes, one of tube 35 and the other of tube 36. Where thebar code generated based on two such reading intervals fails to providea valid consistent reading for central segment 130, component 10 couldbe programmed to produce in a third reading interval, the simultaneousdischarge of both capacitors to simultaneously activate both of theflash tubes 35 and 36 under the control of the central intensity sensor50 which sensor 50 would receive light from a portion 190 of segment 150which would be expected to provide maximum average light intensity. Thecomponent could then be programmed to assemble a complete bar codereading from the three successive reading intervals.

The third interval might be driven by means of a third capacitorconnectable to both tubes 35 and 36 so that the three reading intervalscould be executed in quick succession. Where a first reading operationis unsuccessful for example, because of an incorrect position of theadjustable lens means 30, component 10 may be programmed to immediatelyturn on the label guide indicator means 21 during the interval when thecapacitor means is being automatically recharged for a succeeding secondreading operation. During the recharging operation, e.g., for a timeinterval of about ninety milliseconds, the label guide indicator means21 will remain on, and the reading distance sensor means 22 willrepeatedly measure the distance to the bar code label with anessentially continuous corresponding control of the lens mean by thefocus adjustment means 40. As soon as the component 10 determines thateach of the capacitor means has attained the desired voltage for afurther flash illumination, the image sensor means 11 will be againcleared and a new reading operation automatically carried out. In eachreading sequence as before, one or more of the intensity sensors 50, 51and 52 determines the time point at which the image signal of thephotodiode charge cells is transferred to the CCD shift register stages.Also, after the appropriate integration interval or intervals, thecurrent interrupter switch 16 for a respective capacitor dischargecircuit is operated to terminate the capacitor discharge and extinguishthe flash of a respective illuminator means. The data resulting fromeach integration interval is transferred out of the image sensor means11 via the CCD shift register for processing in component 10. When asuccessful reading is determined by component 10, the correspondingindicator of component 12 will be activated, and for example, it will benecessary to release switch 12 before a further reading operation can beinitiated. Where a given reading operation is unsuccessful, theprogramming of component 10 may be such that the reading operation isautomatically repeated up to, for example, ten times. Should tensuccessive reading attempts be unsuccessful, component 10 would producethe corresponding bad read condition indication via component 120, andagain, for example, it might be necessary for the operator to releaseswitch 12 before 15a further read sequence could be initiated. By way ofexample, once a valid bar code reading was obtained, the programmingcould be such that component 10 could establish communication with ahost computer system, for example, an accompanying portable computer, oran integral host computer. Where no further actuation of the switch 12occurs after a valid reading, the system may be programmed toautomatically power down so that a battery means, for example, withinreader housing 86, would be subject to the minimum drain during inactiveintervals of the reader system.

The foregoing modes of operation could be selected, for example, fromthe keyboard of a hand-held computer carried by the operator along withthe reader unit. The various optional modes of operation could becorrespondingly selected with all modes preprogrammed into thecomponent, or desired respective modes of operation could be obtained byloading the corresponding programming from the hand-held computer intocomponent, as desired. Other special modes of operation can beaccommodated such as machine gun scanning (which might be used inreading lists of labels). In such an operation, switch 12 could be helddepressed while the reader was moved over a series of labels, and theprogramming would be such as to discard identical adjacent bar codereadings. Also, changes could be effected in the operation of the goodand bad read indicators of component 120 and changes could be made inthe allowed number of retries and the like. While the foregoingdescription will enable those of ordinary skill in the art to understandand practice the present invention, the following supplementaldescription is given particularly for demonstrating the availability ofa suitable implementation utilizing low cost presently availablestandard commercial components.

Supplementary Discussion

As an example of implementation of the system of FIG. 1, component 10may be implemented as a Motorola MC68HCII microcontroller. Otherprocessor components which are presently commercially available includea NEC uPD783 10, a National HPC 1 6140, an Intel CMOS MCS8097, and aHitachi HD64180. Some such components would need more external devicesthan others, e.g., such as analog to digital conversion channels, ROM,RAM, EEPROM (or equivalent non-volatile RAM), etc. Generally, as higherspeed processors become available, and processors with more internalmemory and conversion facilities, the utilization of such processorswill be advantageous. FIGS. 5, 10, 11 and 12 herein are shown as usingsignals from the Motorola MC68HCI 1. All other inputs and outputs aregeneral processor pins, so that a drawing showing the processor ofcomponent 10 is not necessary.

In FIG. 5, reference numeral 11-1 indicates a specific component for usein the bar code image sensor means 11 of FIG. 1. By way of specificexample, component 11-1 may comprise a solid state integrated circuitchip such as type TCD106C image sensor or the equivalent. Component 11-1includes a charge coupled device (CCD) shift register driven for exampleutilizing two megahertz clock signals from driver components 201, 202and 203. Where components 201-203 are implemented as type 75361 drivers,these components serve to convert the five volt input logic signals tothe twelve volt level needed to drive component 11-1. Current sources205 and 206 in conjunction with resistors 207 and 208 provide a DCoffset to bring the video output levels from the shift registers into anacceptable input range for the analog to digital converter channels A/D3 and A/D 4 of component 10.

The microcontroller of component 10 could drive each signal linedirectly, but the bit manipulation capabilities of most presentlyavailable processors would provide a very slow preparation and readingcycle time for the case of a bar code image sensor size of 5000 pixels.The circuit shown in FIG. 5 uses an eight megahertz clock 220, FIG. 6,to produce a controlling sequence which can clock out two pixels everymicrosecond from component. The circuit of FIG. 6 allows continuousoperation such as is needed to quickly prepare the component 11-1 for areading operation and also allows single-stepping operation to give theanalog to digital converter channels sufficient time to input eachpixel. The circuit of FIG. 6 allows each shift pulse to be synchronizedwith the clock rate at line 215, FIG. 5, (the 0110 clock line) forproper operation. It is desirable to operate at the highest frequencypossible without unduly complicating or increasing the size of thedriver circuitry, Thus, an image sensor with a higher maximum clockingrate could be selected. In FIG. 6, reference characters 6A through 6Fhave been applied to various lines and the corresponding relatedwaveforms have been indicated in FIGS. 6A through 6F, respectively, byway of explanation of the operation of FIG. 6. The outputs of FIG. 6form respective inputs to drivers 201203 of FIG. 5 as indicated by therespective designations of the corresponding lines in these FIGS. InFIG. 6A, reference numeral 231 indicates the first positive transitionof the clock waveform after the signal (supplied by the aforementionedMC68HCII microcontroller) goes low, or the signal line SCYC goes high.In FIG. 6F, the signal SH follows the dash line 232 if the signal SHENis true. As indicated at 241-244 by dash lines, the cycling continues ifthe signal IVT remains low.

Component 11-1 requires twelve volts for proper operation and a circuitfor providing this voltage from the five volt supply available isindicated in FIG. 7. This circuit should be able to be powered down whennot in use in order to conserve power. A drawback of the circuit of FIG.7 is that when it is turned off, the inductor LI provides plus fivevolts to the plus twelve volt circuits unless a transistor Q4 is addedto block the five volts.

Line 251 in FIG. 7 receives a switched plus five volts for supply to thedrivers 201-203 of FIG. S. Line 251 may also supply five volts to anyother circuit which is not needed when the twelve volts is off. The fivevolts at line 251 is switched off with the plus twelve volts at line 252to completely power down the image sensor component 11-1 of FIG. 5 anddrivers 201-203. An output line 253 in FIG. 7 provides five volts whenthe twelve volts are shut off and provides twelve volts when the line254 (+(+12 ENB)) is enabled. The voltage at line 253 is used to drive anoscillator 255 of FIG. 8 which is utilized in the present commercialinstant bar code reader. Circuits suitable for implementing FIG. 7desirably exhibit low cost, high efficiency and least number of parts.

FIG. 8 illustrates a suitable high voltage generator circuit forgenerating approximately 300 volts for the xenon flash tube 260illustrated in FIG. 9. The circuit shown in FIG. 8 is similar to that ofthe present commercial instant bar code reader. The transformer TI ofFIG. 8 uses a gapped core and is actually a transforming inductor.Magnetic energy is stored in the core on respective first half cycles,and on opposite half cycles the field collapses and generates very highsecondary voltages which are used to charge the flash capacitor 261. Byway of example, transformer TI may be a Ferroxcube 1408 PA 250-3B7 witha turns ratio of forty-three to one. Transformer TI exhibits a 100microhenry inductance at its primary side and 185 millihenries on thesecondary side. This type of circuit will continue to charge thecapacitor 261 beyond its rating, if not stopped, so a comparator 262 isused to control the oscillator 255. The output of comparator 262 at 263is a logic signal that indicates to component 10 that proper flashvoltage is available. The five-twelve volt supply line 253 is used toenergize oscillator 255 in the circuit of the present commercial instantbar code reader since the oscillator component 255 drives transistor 266more efficiently when running from twelve volts. However, the flashcapacitor charging circuit must also run from plus five volts. Thecircuit of the present commercial instant bar code reader provides arelatively high initial input current of up to two amperes duringcharging of capacitor 261. This only lasts a few milliseconds, but itrequires the host providing power to the reader to be able to handle thehigh current surge. A more uniform charging current over the duration ofthe allowed charge time, say a relatively constant charging current offour tenths ampere over a time interval of about one hundred and fiftymilliseconds would be more desirable. If it is permissible to rechargethe flash capacitor only four times per second, for example, rather thanten times per second, component 10 may be programmed to control thecharge rate to allow the lowest current level, for example, a chargerate of 250 milliamperes over a charging interval of 250 millisecondscould be switched on by the programming where a flash rate of four timesper second would be acceptable.

Much of the flash tube illumination circuit shown in FIG. 9 is used inthe present commercial version of instant bar code reader. The additionof component 16-1 corresponding to flash current interrupter switch 16,FIG. 1, is advantageous to interrupt the flash when sufficient light hasbeen detected by the intensity sensor means 14. Without a means forinterrupting the flash, the flash capacitor such as 261, FIG. 8, will bedrained, producing additional unneeded light. Furthermore, the capacitorwill have to be recharged from zero requiring that much more current andelapsed time. Thus, the use of intensity sensor means 14 and switchmeans 16 not only reduces the power requirement so as to increase theoperational time of the system in portable applications using batteries,but also enhances the performance of the unit by enabling more rapidflashes of the illuminator means. Input 270 (FLASH VOLTAGE DISABLE) FIG.8, and input 271 CONT and input 271' (FLASH), FIG. 9, can be controlledfrom component 10. Because the output of the xenon flash tube 260 is ofsuch short duration (about twenty microseconds), processor interventionto control integration time is not practical with presently availableprocessors.

Accordingly, FIG. 9 illustrates a light sensor means 14-1 correspondingto intensity sensor means 14, FIG. 1, as being coupled with the switch16-1 and the illuminator means indicated generally at 15-1 by means of ahardware circuit which can be trimmed for example, as indicated byvariable resistance means 272 associated with conversion circuit andtimer component 273. The circuit of FIG. 9 not only causes a "set"output pulse at 275, FIG. 9, to initiate the shift sequence in the CCDcomponent 11-1, FIG. 5, via input 275-1, FIG. 6, but also stops theflash tube by interrupting the flash tube current utilizing component16-1, which may, for example, be a Motorola Gemfet, type MGP2ON50.Component 16-1 needs to be able to handle the forty amperes peak duringdischarge of capacitor 261.

The microcontroller of component 10, FIG. 1, may be connected to hostcomputer with a six conductor shielded, coiled cable such as indicatedat 122, FIG. 1, by means of circuitry, such as shown in FIG. 10. Theshield should be a braid or spiral wrapped type, but not a foil with adrain wire. Each wire should have a number of twists per inch to give itmaximum flexibility. There are two lines 281 and 282 driven by thereader that can be programmed as ASYNC or SYNC data out, and two linesinto the reader, a line 283 serving as a programmable serial data inline, and a line 284 dedicated as an activelow reset line. The other twolines 285 and 286 are power (plus 5 V) and signal ground.

FIG. 10 shows Fairchild type 74AC14 devices as being utilized for bufferand receiver components 291-295. This component was used because of itsbuilt-in hysteresis and balanced high output drive (24 mA) capability.The various resistors and diodes are used for ESD (electrostaticdischarge) protection up to 25,000 volts. A six-pin connector may beused at 296 of a style similar to that used on industrial camera cables.FIG. 11 shows an implementation 20-1 of the automatic reading distanceadaptation means of FIG. 1. In FIG. 11, a DC motor 103-1 is controlledfrom the microcontroller of component 10 via power drivers 302 and 303.The drivers 302 and 303 are selectively energized so as to drive themotor 301 in the correct direction for improving focus. A feedbacktransducer 305 is shown as having a movable tap 306 mechanically coupledwith the focus barrel 30 and thus being driven jointly therewith bymotor 103-1 so that analog to digital converter channel A/D 2 receives aresistance value in accordance with the actual adjusted position of theoptics 30. FIG. 12 shows an implementation 22-1 of reading distancesensor means 22 including an ultrasonic distance measurement circuit 310associated with ultrasonic transducer 38. A disable line 311 (DENB) forthe circuit 310 may be controlled by the microprocessor component 10 ofFIG. 1, and the analog distance measurement value may be supplied viaoutput line 312 to an analog to digital converter channel A/D 1. Allparameter and calibration/conversion tables for the ultrasonic distancemeasurement can reside in the memory of component 10.

The audio indicator of component 120 can be driven from a frequencycreated by the processor of component 10, if desired. All light emittingdiode indicators are controlled by the processor as indicated in FIG. 1.The switch 12 connects to a processor input pin but should be able tointerrupt and wakeup the processor if the reader is in a standby/sleepmode. Label guide indicator means 21 preferably provides two indicatorbeams as previously described, it being conceivable to produce the twobeams 5from a single light emitting diode which is directed initially toa partially reflecting mirror which is also partially transmissive alongthe length of the photosensor array 13 to a completely reflective mirrorat the opposite end of the array. The marker light emitting diode ordiodes are turned off during the clearing of the image sensor and theenergization of the flashable illuminator means to prevent theirsaturating the image sensor with light and thus interfering with anaccurate bar code reading.

It is desirable to maintain the largest depth of field possible (foreach fixed position of lens arrangement 30) to not only allow easier andfaster focusing, but also to allow focusing on uneven surfaces such asthe curved bar code configuration presented by label 131 indicated inFIG. 2.

For the purpose of enlarging the depth of focus, and increasing thespeed of adaptation of the reader to a given bar code configuration, thereader housing 10 may accommodate a plurality of adjustable lens meanswith respective overlapping depths of field so that for fixed positionsof the lens means, the depth of field is greatly enlarged. Such multiplelens barrels could be adjusted simultaneously so that the lens systemsin each position thereof have the total depth of field greatly enlarged.As an example, mirror 82, FIG. 3, could have an upper segment bentoppositely to the segment receiving an image at axis 64, so that asecond bundle of reflected light would be directed upwardly as viewed inFIG. 3 toward a second mirror similar to a mirror 83 but with anopposite inclination so that the second image is directed rearwardly inhousing 86 parallel to path 81 but above mirror 82, the second imagepassing through a second lens barrel similar to barrel 90 but located,for example, rearwardly of barrel 90 so as to focus on bar code imagescloser to the window 33, for example, than the barrel 90.

FIG. 13 diagrammatically illustrates the optical components of such anarrangement, which includes a window 33A, a flash tube housing 75A, amirror segment 82A, a mirror 83A, a mirror 84A, a lens barrel 90A, and asensor housing 124A, respectively, corresponding to components 33, 75,82, 83, 84, 90, and 124 of the arrangement of FIG. 3, and providingoptical axes 60A and 64A and paths 80A and 81A, respectively,corresponding to paths 60 and 64 and paths 80 and 81 of FIG. 3. Thearrangement also includes an upper mirror segment 82B bent oppositely tothe segment 82A and receiving an image at an axis 64B to direct lightupwardly to a mirror 83B having an inclination opposite to that of themirror 83A. A second image is directed rearwardly along an axis 81Bparallel to axis 81A to pass through a second lens barrel 90B locatedrearwardly with respect to barrel 90A so as to focus on bar code imagescloser to the window 33A. One dimensional photosensor arrays 13A and 13Bwithin sensor housing 124A and 124B are connected to control andprocessing means 10A.

Distance measurement means 38 may be coupled with control and processormeans 10A in order to provide range information to processor 10A suchthat the proper focal path A or B may be selected. This may beaccomplished by simply allowing the processor 10A to operatively selecta particular one-dimensional array (124A, 124B).

In another example, a plurality of mirrors analogous to mirror 82 couldbe arranged at respective different distances from the window 33, suchthat all of the image paths would traverse the same lens barrel 90 butthen would be focused onto respective different image sensors, forexample, by means of multiple mirrors analogous to mirror 84 but locatedat respective different distances from the center of lens barrel 90.Such a multiple image path lens system would, for example, provide pathswithin the reader of length greater than the length of the image path at64, 80, 81, 60 of FIG. 3, and also 25 optical image paths in the housing86 of length shorter than the length of the path 64, 80, 81, 60. Thevarious image paths together could provide the result that the depth offield for each respective image path would overlap with the depth offield of other of the image paths, so that the single lens barrel suchas 90 would cover images anywhere within a range in front of a window 33corresponding to a multiple of the depth of field provided by the imagepath 64, 80, 81, 60 by itself. Thus, through proper multiple mirrorplacement and folding of the optical image paths, a common lens barrelassembly could focus on multiple depths in front of the reader, theprocessor component 10 selecting the respective image sensor or imagesensors from which to assemble the pixels of a complete bar codereading. FIG. 14 diagrammatically illustrates the optical components ofsuch a multiple image path single lens system, which includes a window33C, flash tube housing 75C, mirror 83C, mirror 84C, lens barrel 90C andsensor housing 124C, corresponding to components 33, 75, 83, 84, 90 and124 of FIG. 3, and components 33A, 75A, 83A, 84A, 90A and 124A of FIG.13. The system of FIG. 14 further includes a plurality of mirrors 82C,82D, 82E, 82F and 82G at respective different distances from the window33C, such that all image paths traverse the same lens barrel 90C, to befocused on different image sensors of an array 13C which are within ahousing 124C and which are connected to control and processing means 10Coperative to select the respective image sensor or image sensors fromwhich to select the pixels of a complete bar code reading. With such amultiple image path single lens system arrangement, the lens systemarrangement could remain stationary, avoiding the requirement for amotor and movable parts, and also providing for instantaneous reading ofa label whose various segments came within the depth of field of one ormore of the respective image paths and associated image sensors.Further, distance measurement means 38 may be coupled with control andprocessor means 10C in order to provide range information to processor10C such that the proper focal path C, D, E, F, or G may be selected.This may be accomplished by simply allowving the processor 10C tooperatively select a particular line 13C of the two-dimensional array124C.

It will be apparent that many further modifications and variations maybe effected without departing from the teachings and concepts of thepresent disclosure.

We claim as our invention:
 1. In a bar code reader system, a hand-heldbar code reader positionable by hand at varying distances from a barcode to be read and operable for reading bar codes at distances fromsaid reader within a certain operative range, said reader comprising:(a)bar code sensor means for generating an output signal in accordance witha bar code image incident thereon; (b) distance measurement means forautomated reading of distances of a bar code from the hand-held bar codereader over a certain measurement range which exceeds said certainoperative range for reading of bar codes; (c) reading distanceadaptation means for automatically adapting the reader to the reading ofa bar code at varying distances therefrom with the said operative rangeby causing an image of the bar code to be substantially focused at theimage sensor means; (d) enabling means for enabling a bar code readingoperation, and control means coupled with said enabling means and saiddistance measuring means and operative in response to enabling of a barcode reading operation by said enabling means and in response to readingby said distance measurement means of distances within said operativerange for automatically controlling the reading distance adaptationmeans during movement of the reader relative to a bar code within saidoperative range to tend to establish and maintain a focused bar codeimage at the image sensor means; and (e) said reading distanceadaptation means including optical path means providing a plurality ofselectable paths to said image sensor means of different effective focallengths.
 2. The optically readable information set reader system ofclaim 1, wherein said image sensor means includes at least onephotosensitive array.
 3. The optically readable information set readersystem of claim 2, wherein said at least one photosensitive array is aCCD.
 4. The optically readable information set reader system of claim 2,wherein said image sensor means monitors the reflected light from aninformation set to be read during a reading operation, and whereinintegration is terminated once an optimum sample of the reflected lightimage has been received.
 5. The optically readable information setreader system of claim 1, wherein said reading distance adaption meansincludes at least one of label guide indicator means and readingdistance sensor means.
 6. The optically readable information set readersystem of claim 5, wherein said reading distance adaption means includesat least one lens.
 7. The optically readable information set readersystem of claim 6, wherein said at least one lens focuses the reflectedlight image of an information set to be read on said image sensor means.8. The optically readable information set reader system of claim 7,wherein said at least one lens reflects said reflected light image of aninformation set to be read on said image sensor over a range whichexceeds said certain operative range for reading of information sets andfocuses said reflected light image of an information set to be read onsaid image sensor within said operative range.
 9. The optically readableinformation set reader system of claim 8, wherein said reading distanceadaption means includes indicator means for indicating to an operatorwhen said system is within said operative range.
 10. The opticallyreadable information set reader system of claim 1, wherein said readingdistance adaption means includes at least one marker beam directed intothe field of view of the reflected light image sensor.
 11. The opticallyreadable information set reader system of claim 10, wherein said atleast one marker beam is at least two marker beams and said marker beamsextend from opposite ends of the information set image sensor.
 12. Theoptically readable information set reader system of claim 1, whereinsaid at least one lens has through the lens beam optics such that thespots produced by said marker beams delineate the field of view and thedesired position of an information set to be read.
 13. The opticallyreadable information set reader system of claim 1, further comprising aflashable illuminator.
 14. The optically readable information set readersystem of claim 13, wherein a capacitor discharge energizes saidflashable illuminator.
 15. The optically readable information set readersystem of claim 14, wherein the capacitor discharge current isinterrupted.
 16. The optically readable information set reader system ofclaim 15, wherein said capacitor charge is monitored.
 17. The opticallyreadable information set reader system of claim 1, wherein said imagesensor means is an adaptive image sensor system capable of enabling asuccession of readings of a given information set with reflected lightfrom respective different segments of said information set so as to readinformation sets residing on curved substrates.
 18. The opticallyreadable information set reader system of claim 17, wherein saidadaptive image sensor system includes means for simultaneously readingcode segments at different focal lengths within a depth of field. 19.The optically readable information set reader system of claim 18,wherein said simultaneous reading means reads at least two code segmentswithin a single integration time.
 20. In an optically readableinformation set reader system, a hand-held bar code reader positionableby hand at varying distances from an information set to be read andoperable in a stationary position relative to an information setpositioned at a distance from said reader within a certain operativerange, said reader comprising:(a) a plurality of optically readableinformation set sensors for generating at least one output signal inaccordance with an information set image incident thereon, and a readingdistance adapter for adapting the reader to reading an information setat varying distances therefrom by causing an image of the informationset to be substantially focused at the image sensor, said readingdistance adapter including an optical path generator for providing aplurality of selectively usable paths; and (b) a path use controller forselecting the corresponding one of said selectively usable paths whichprovides the focal length most closely approximating the effectiveoptical distance to an information set to be read.
 21. In an opticallyreadable information set reader system as defined in claim 20, saidoptical path generator including at least two lenses through whichseparate ones of said plurality of selectively usable paths extend. 22.In an optically readable information set reader system as defined inclaim 20, said optical path generator including a lens through whichcommon portions of a plurality of said paths extend.
 23. In an opticallyreadable information set reader system as defined in claim 20, whereinsaid plurality of optically readable information set image sensor meansis a photosensitive array.
 24. In an optically readable information setreader system as defined in claim 23, wherein said photosensitive arrayis a two-dimensional array.
 25. In an optically readable information setreader system as defined in claim 23, wherein said photosensitive arrayhas a pixel size of not less than seven (7) microns.
 26. In an opticallyreadable information set reader system, a user supported information setreader positionable by a user at varying distances from an informationset to be read and operable in a stationary position relative to aninformation set positioned at a distance from said reader within acertain operative range, said reader comprising:(a) an opticallyreadable information set sensor for generating an output signal inaccordance with an information set image incident thereon, and a readingdistance adapter for automatically adapting the reader to the reading ofan information set at varying distances therefrom by causing an image ofthe information set to be substantially focused at the image sensor,said image sensor including a plurality of portions and said readingdistance adapter including a passive optical path generator providing aplurality of selectively usable paths to said plurality of portions ofsaid image sensor of different effective focal lengths; and (b) path usecontrol means for effecting use of the portion of said image sensor andthe corresponding one of said selectively usable paths which providesthe focal length most closely approximating the effective opticaldistance to an information set to be read.
 27. The optically readableinformation set reader system of claim 26, wherein said sensor is aphotosensitive array.
 28. The optically readable information set readersystem of claim 26, wherein said array has a pixel size not less thanseven (7) microns.
 29. In an optically readable information set readersystem, a user supported information set reader positionable by a userat varying distances from an information set to be read and operable forreading information sets at distances from said reader within a certainoperative range, said reader comprising:(a) a plurality of opticallyreadable information set sensors for generating an output signal inaccordance with an information set image incident thereon; (b) a readingdistance adapter for automatically adapting the reader to the reading ofan information set at varying distances therefrom; (c) a computer forenabling an information set reading operation; (d) a controller operableby said computer for controlling the operation of said reading distanceadapter such that optically readable information sets may be read bysaid reader over a range of distances from said reader; and (e) saidcontroller being automatically operable to repeatedly actuate saidreading distance adaption means as the reader is moved toward anoptically readable information set.
 30. In an optically readableinformation set reader system as defined in claim 29, wherein saidplurality of optically readable information set image sensor means is aphotosensitive array.
 31. In an optically readable information setreader system as defined in claim 30, wherein said photosensitive arrayis a two-dimensional array.
 32. In an optically readable information setreader system as defined in claim 30, wherein said photosensitive arrayhas a pixel size of not less than seven (7) microns.
 33. In an opticallyreadable information set reader system, a user supported information setreader positionable by a user at varying distances from an informationset to be read and operable for reading information sets at distancesfrom said reader within a certain operative range, said readercomprising:(a) a plurality of optically readable information set sensorsfor generating an output signal in accordance with an information setimage incident thereon; (b) a computer for enabling an information setreading operation; and (c) a memory associated with said computer forstoring at least a portion of the output signal generated by said sensorduring a reading operation and said memory in association with saidcomputer for assembling a first portion of an output signal generated bysaid sensor during a reading operation with a second portion of theoutput signal generated by said sensor during a reading operation. 34.The optically readable information set reader system of claim 33,further comprising a reading distance adapter for adapting the reader toread optically readable information sets over a range of distances fromsaid reader.
 35. The optically readable information set reader system ofclaim 34, further comprising a controller operable by said computer forcontrolling the operation of said reading distance adapter.
 36. Theoptically readable information set reader system of claim 35, whereinsaid controller being automatically operable to repeatedly actuate saidreading distance adaption means as the reader is moved toward anoptically readable information set.
 37. In an optically readableinformation set reader system as defined in claim 33 wherein saidplurality of optically readable information set image sensor means is aphotosensitive array.
 38. In an optically readable information setreader system as defined in claim 37, wherein said photosensitive arrayis a two-dimensional array.
 39. In an optically readable information setreader system as defined in claim 37, wherein said photosensitive armyhas a pixel size of not less than seven (7) microns.
 40. In theoptically readable information set reader system as defined in claim 33,wherein said sensors provide said memory associated with said computer.41. In the optically readable information set reader system as definedin claim 33, wherein said array further comprises a shutter wherebyimage blurring caused by user movement is reduced.
 42. In the opticallyreadable information set reader system as defined in claim 33, furthercomprising flash illumination means.
 43. In the optically readableinformation set reader system as defined in claim 33, further comprisingmarker beams for targeting an information set to be read.
 44. In theoptically readable information set reader system as defined in claim 43,wherein said marker beams at least partially illuminate an opticallyreadable information set to be read.
 45. In the optically readableinformation set reader system as defined in claim 43, wherein saidreader has a range of at least three (3) inches.